Question for well experienced roofers
I asked this question to another BT buddy and got his perspective and it’s leaving me concerned, so thought I’d ask the group out here….
I have an addition (workshop over slab) we’re doing now. We sheeted the roof with 4ply CDX that is 15/32. onto 16″ oc trusses. Took us longer to sheet it than thought so when we were done we quit, didn’t felt it or anything intending on protecting it the next day on Fri morning. Unfortunately I did not look at forecast. We installed it this past Thursday. It rained Thurs night before we had a chance to protect it. Come Fri AM it was soaking wet, we couldn’t cover it as we were unable to put down the ice/water guard since roof deck must be dry for adhesion (BTW the HO wants entire roof I&W guarded, no felt). As we worked during the day it was cloudy so we put in the skylights figuring the roof would continue to dry out. Well, it started to rain…again. Steady. We quit and went home but I remained concerned about the water on the decking.
Saturday, you guessed it…it rained more, and roof is still unprotected.
On Sunday it is raining yet again. this is almost 3 days of steady rain on this roof deck. I decide enough is enough so we go over and decide to cover the roof with a 30×30 tarp that I went out and got. When I got on teh roof I saw a few places the decking has bubbled, like a large bubble between the 16″ truss spans, and I saw other areas of humping of the roof. A few places I saw the decking swollen to greater than the 15/32″ that it’s supposed to be. I also saw a few places where one sheet of plywood was lower (like it sunk a bit) than the adjacent sheet butting up against it, making it look like it was pushed down instead of being even across the joint to the adjacent seam.
It’s still raining here, but the tarp is covering MOST of the roof now, 97% of it at least.
Am I screwed, is the ply forever damaged, or will it survive once it dries out? Have I compromised the integrity of the decking now to where it will cause me problems later? I”m concerned because this is my first time decking a roof where it got wet, and I want to be known to produce a quality product that will give years of troublefree service to the owner.
Thoughts please?
Replies
If you are going with archy shingles and not three tab, it "should" be OK. It happens often to framers.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
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Yeah, it'll be architect shingles. Thing is, it won't get shingled til th Fall sometime....which is why HO wanted to use I&W guard for whole roof. it'll get shingled when we get the rest of his addition done on the main house.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
When the rain stops don't rush to cover it up. Inspect after a couple of days in the sun, might have to replace some, but probably not to much.
Thank you..that is in line with advice given to me, so confirmation only gives me more peace of mind.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
I'm a carpenter not a roofer.. just thought i would share a recent experience
If the whole thing is being I&Wed I think it will be fine. We framed a house, archy called for 3/8" on the plans.. contractor we were working for stepped it up to 1/2" as it was trusses on 24 o.c. Roofers came.. just hacked away the bubbles... there were two big ones.... like 8"x3" bout an inch high.
Ive seen 3/8 on roofs, but never on 24" spacing- WTF was the archy thinking?
Believe it or not, some codes permit that. But an archy who specs that just because some jerk code-writer was having a bad hair day in his armpits really oughta consider another line of work....
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I have no idea... it was a weird job.. specced 1/2 ply sheathing(sheeting??) not OSB which is the norm and then complete other end of the spectrum wanted a 12" sono with 24" bigfoot for a entry deck, no roof overhead with four stairs up to it total sq 3'x3', lagged onto the wall on two sides.
Just got done reroofing one that was 3/8 cdx on 24 o.c. trussed, replaced only 4 sheets that has water damage. Built in the early 70's.
The first house I built for myself had 3/8" ply on 24" centers. It worked fine. I re-roofed it after about 15-20 years and laid a second layer of dimensional shingles on top of the three tab.
It's still fine.
I would get the tarp off as soon as it stops raining, if not before. The tarp will trap moisture and actually keep the plywood wetter than if it is just left out in the rain. The worst subfloor damage I ever experienced came from a job where the owner insisted on covering the floor with plastic during a rainy spell.
The other observation is that in my experience, the plywood that is going to delaminate does so right away. I had a project once that took the whole season to frame. Some of the floor plywood delammed with the first rain, and in spite of many, many wettings after that, the rest of the floor remained unharmed, except for some discoloration.
Have you looked at Something like RoofTopGaurd II or Titanium UDL? I'm not sure wht kind of walking surface that I&WS will give you, but those synthetics will easily live in the elements for MONTHS while getting walked on without deterioration - plus they have a textured surface so you don't slip!
Tu stultus es
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
Look, just send me to my drawer. This whole talking-to-you thing is like double punishment.
Am I screwed,
I dunno; ask Mrs. Wonka, not a buncha roofers. ;-)
is the ply forever damaged, or will it survive once it dries out?
It has a better chance of surviving this than Beaver Barf, but you certainly haven't done the ply any favours. You're going to have to check each sheet individually after it all dries out. Look especially for big patches of delamination.
OTBS I know 2 guys who had to build their own places on the cheap and bought stacks of water-damaged ply for fifty cents on the buck. Laying that stuff was no picnic but it didn't turn out too badly....
As mentioned, any inequalities in edge thickness will be better hidden by 'archy' shingles than by standard 3-tabs.
Have I compromised the integrity of the decking now to where it will cause me problems later?
I would have to say hmmmmmm. Half-inch is minimal for roof sheathing IMO except for a pretty steep roof or one in an area with almost no snow loading. So you don't really have any extra 'beef' you can afford to lose in the first place. It will be a close call and you're gonna have to make it: You can see the stuff better than we can.
Just don't lie to yerself when it comes time to bite the bullet or not.
Sorry, wish I could be more encouraging....
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
Not a pro, but I'll give ya my 2 cents.
Let it dry as long as possible. Once you put the I&W on, all the drying will have to come from the bottom. If you let the ply dry just long enough to install the I&W to a dry board, you may have moisture just below the surface that has to migrate thru the ply to get out (could be a long process)
If you just had felt on top then the moisture could come up and thru the felt and shingles.
Prior to putting the I&w I would screw any bubbles or delaminations, maybe add some screws to any perimeter that looked iffy.
Good luck
The roof bubbled because you didn't leave enough space between the sheets. You probably should have run the saw throught the joints before you tarped it.
Four ply tends to bubble easily especially if you don't space it.
What is the species of the ply? That will often give you a clue as to how much you need to space it.
It will probably be okay after it drys but if the bubbles don't settle down you might have to cut out a few spots.
yep totally screwed.
tear it all off and start over.
If You don't believe me then just google up roof failures in the PNW.
Just joking..
Roof sheathing out here gets wet. Everything here gets wet.
Period.
You start a project between say early October until say late June and I will pretty much guarantee you the sheathing will get soaked.
That leaves you 3 months of non rain if you are lucky and don't get one of the summer storms.
(Ask bobbys how many roofs he has done that were dry. ;-0 )
Bubbles can be caused by no expansion space, different rate of expansion contraction of the face plys, bubbles or voids in the filler plys, and delaminations (often caused by bad glue ups in the ply).
Most settle down after drying, some you cut out, some you add a block under the bubble and screw or nail it down again, most get ignored.
I check the bubbles out, if I feel it is a delamination I replace that part of the sheathing. the rest I ignore.
Should be OK once you let it dry out, but you do need to get it dry! Did you leave spaces between sheets? if not, that accounts for some of the humps and dips as the tight butted swelled in size.
You might need to run a couple drywall screws into the blisters to tie them down.
Next time use advantec or their zip sheathing, or watch the forecast or keep a tarp at the ready.
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If the whole roof were showing big humps....I might think that it was a spacing issue. But if I'm reading this right, it's bubbled randomly, and the layer of veneer will tear off in those spots. I see that all the time with sheets sitting in the pile, before they get put on a roof. I think the 4-ply fir cdx that comes out of the mills these days is junky. Don't remember half the delam problems 20 years ago. Curious, tho in regards to your advice as to drying the roof out complete. When you were roofing(which I know you did a ton of)if it rained the night before you started a new job that was a bare frame, you didn't start til it dried out? I've shingled a whole lot of roofs the day after 3 days of rain,papered it and shingled over wet ply, and I can't say that I've seen a problem with any of them, bubbling or any other defect.I find it hard to believe that if you pulled up the shingles after a week or two of sunny weather, there would be any moisture there at all. Don't you think that once the sun hits it and the attic warms up to 90 that it dries out whatever moisture may be left? Not arguing, but curious. Seems that in a wet spring, unless you papered a roof and shingled that day, there would be times where the rain/ dryout process would make getting any work done tough.Bing
As a roofing sub, my procedure has always been to have good communications with the builder, and get dried in immediately. Lots of times we finished up a roof at 2PM and rode over to another one to get it papered in. That allowed a week or two for the builder to get his facia done and plumbing stacks up thru and shingles stocked delivered on the roof. Some builders had their carpenters do the dry-in work.But there were sometimes roofs that did get rain before the tarpaper. We went right over that even when wet, but there was still a week or two before shingles for the warm sun on black paper to pull the moisture out.But in this case in this thread, the addition of I&W over the entire roof is likely to make steam and even more blisters in this ply.I would use Rooftopgaurd myself. I have had it on a couple different roofs for up to five months with carpenters, painters, and masons walking and working on it without wearing it out. Then air could still let vapour come off the top side of the playwood
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So what did you do if, after papering, during the period before it got shingled, it got rained on off and on? My "policy" if you will, has always been that, with felt, if we papered it, we shingled it. If it got wet and then dried out.....it would be a big wrinkled mess when we went to cover it, which leads to putting relief cuts in the paper, which leads to it being less of a safeguard, imo.I'm with you on the Rooftopgaurd.... great to be able to cover it once, no wrinkles, bigger roll so it goes down quicker, great idea for a zillion reasons. I've gotten to the point where we try to schedule it so that if we board in a section of roof....it gets covered that day....takes a lot of the aggravation out of the whole deal, plus means there's some "weathertightness" (is that a word?) to do strapping and partitioning on rainy days before the roof is tight.Bing
"So what did you do if, after papering, during the period before it got shingled, it got rained on off and on? My "policy" if you will, has always been that, with felt, if we papered it, we shingled it. If it got wet and then dried out.....it would be a big wrinkled mess when we went to cover it, which leads to putting relief cuts in the paper, which leads to it being less of a safeguard, imo."I'm not all that sure I understand all that, but it seems like you are saying that felt that gets wet wrinkles.That is true, but it also tightens up when it gets dry again. The only felt I've seen stay wrinkled is when it is not applied tight and straight. Stretch and nail it tight, and shingle it dry and there is not problem.
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Piffin
But shingle it wet and wrinkled and they will telegraph thru for years to come.
We have a steep church roof in town with wrinkled tar paper underneath.
It is pretty obvious.
Roofers Select by Certainteed doesn't wrinkle nearly as much as regular tar paper. I used to only us 30 lb but the quality got so irregular that I switched to Roofers Select.
I haven't tried any of the new synthetic stuff yet. I just showed up in the yard this spring.
Rich
all true, but I don't shingle over it wet! I started this exchange by pointing out that he has to let it dry first. Maybe I am reading things wrong, but somehow get the impression guys are arguing with me while telling me the same thing I had said.
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Piffin
Wrong impression. Just adding not arguing.
I am sorry if I gave the impression of arging.
I won't dream of arguing with you.
The discussion was talking about wet tar paper and I have an example I drive by often, of doing it wrong. I was just trying to say it won't straighten out later under the shingles.
Like you I have seen very wrinkled TP get flat as a drum with just a couple hours of sunlight.
Rich
Edited 5/6/2009 7:22 am ET by cargin
There was a couple guys before you too...and was reading yours on first cup of coffee...Most guys I see do not stretch their tarpaper tight when installing it either, IMO. They just roll it out and nail it - which is just asking for wrinkles, even without the rain or dew.
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Piffin
I forgive you for being grumpy before you have had at least 2 cups of coffee. LOL
Rich
Edited 5/6/2009 12:30 pm ET by cargin
Most definitly not arguing...just politely questioning...:)
I agree as to the stretching it tight comments.....just never seems to flatten out as flat as it started after a lot of rain.
New stuff is the way to go tho, hands down.
See? we all agree! Though I've had 27 cups of coffee by now.
Bing
Just finished my fourth - but it is PM now!One of those things that you can't read mood correctly online...oh my.
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Bing187,Is there any reason why you shouldn't I&W an entire roof that is dry?
I ask because a roofer once said that it will trap moisture in the roof
deck and cause rot. I beleive he was speaking of moisture from the
interior of a home, not because the deck got wet before the I&W shield.
Granted, the underside of a roof should be vented anyway, so I didn't
his logic. Any thoughts on this?Thanks
I sure hope not, because I've I&W'd a bunch of roofs when they were dry.......I usually use I&W on whole (mainly porch) roofs @ 4/12 or less, tho that really just covers a 3 or a 4, because I'm not a fan of shingles under a 3/12 pitch. Don't see any reason why it would trap moisture any more than anything else would......as you said, moisture issues should be addressed with good ventilation practices. I've seen roofs with inadequate ventilation when doing re-roofs, and it's evident by mildew, etc. on underside of roof ply. The roof deck, however, was still dry when stripped.I will say this, tho. In the last few years, I've had occasion to tie into some roofs with additions and whatnot, where I've needed to step back and blend into roofs with the 3' row of I&W at the bottom.....my experience has been that the bottom rows of shingles on the 3'of I&W were glued down something fierce to the i&w......It's not going to be smooth stripping when the roofs start needing re-done that have that bottom row of i&W, never mind a complete roof with it.Bing
Bing187Thanks for the reply. Yes, I've also used I&W for entire roof areas for various reasons. For low slope it is a no-brainer. From my POV it was extra money out of my pocket, but I felt that overall it added extra protection to the interior of the finished house on remodel jobs. It also gave me peace of mind knowing that the I&W was in place even though the finished roof wasn't completed (ie. no sleepless nights worrying that a tarp broke free from the wind while listing to the rain and wondering if there were any leaks), as well as the knowledge that I did a bit of extra that would serve the customer for years to come. Granted, my work is not track housing where the cost of the extras can quickly multiply out and add up to a lot of money. All things considered, I count on I&W shielding entire roof areas of jobs that I work on, that is why it through me when a roofer said it would couse rot.
I don't believe I&W will cause rot in a properly insulated and vented roof either
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How long is the I&W warranted to withstand UV?
Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein (or maybe Mark Twain)
"Get off your dead #### and on your dying feet." Mom
"Everything not forbidden is compulsory." T.H. White, The Once and Future King
How long is the I&W warranted to withstand UV?
Varies from brand to brand, but 90 days max.http://www.quittintime.com/ View Image
good point.
I forget the exact but ran into that Q once ...
it wasn't long.
not like "forever" with tar paper.
he'd probably be better papering it then tear off the paper before ice guarding when the time comes.
Jeff Buck Construction
Artistry In Carpentry
Pittsburgh Pa
for warrantee purposes, it is 30-90 days, depending...but in reality, I've seen some that was on for over two years and still performing.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
It's a good question to ask. It's amazing how many building materials that UV degrades. About the only things immune are concrete, stone, and steel, and I'm not so sure about steel.Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein (or maybe Mark Twain)
"Get off your dead #### and on your dying feet." Mom
"Everything not forbidden is compulsory." T.H. White, The Once and Future King